<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>代码雨</title>
  <style>
    * {
      padding: 0;
      margin: 0 auto;
      box-sizing: border-box;
      overflow: hidden;
    }
  </style>
</head>
<body>
  <canvas id="canvas"></canvas>
</body>
<script src="./js/canvas.js"></script>
</html>